Technological Field
The present disclosure relates to an electrophotographic image forming apparatus.
Description of the Related Art
An image forming apparatus using a technique of the electrophotographic process (e.g., printer, copier, facsimile) commonly forms an electrostatic latent image by irradiating (exposing) a charged photoreceptor with laser light based on image data. Then, toner is supplied from a developing device to the photoreceptor on which the electrostatic latent image is formed, whereby the electrostatic latent image is visualized and a toner image is formed. Further, the toner image is directly or indirectly transferred to a paper sheet and heated and pressurized at a fixing nip, whereby the toner image is formed on the paper sheet.
Meanwhile, in recent years, products need to be environment-friendly. As an example thereof, it is required to extend a service life of a replacement part of a product, and to improve prediction accuracy of a replacement timing.
Since a photoreceptor has a comparatively short service life among the replacement parts, it is required to improve the prediction accuracy of the replacement timing.
As a method for detecting the replacement timing of the photoreceptor, there has been known a method for predicting a service life on the basis of an integration time of a rotation time of the photoreceptor as disclosed in JP H05-188674 A1.
Besides, there has been known a method for predicting a service life on the basis of a charging application state together with the rotation time as disclosed in JP H10-039691 A1.
Meanwhile, as the number of printed sheets per unit time increases, the temperature around the photoreceptor inside a machine rises so that resistance of a charging roller decreases. Accordingly, the amount of current flowing to the photoreceptor increases. This increase in the current amount may shorten the service life of the photoreceptor.